S&P 500 Adds Navient, Under Armour

Navient replaces SLM Corp., which split itself into two companies: Navient, and a consumer-banking operation that will continue under the Sallie Mae brand. Under Armour replaces Beam Inc., which was acquired by Suntory Holdings Ltd.

The move to add Under Armour to the S&P 500 comes after larger rival Nike Inc. last year was added to the Dow Jones Industrial Average. Athletic-gear makers have reported strong demand in the U.S. in recent years, and Under Armour has also pushed to become a more global brand that can compete with Nike and Adidas AG.

S&P is part of McGraw Hill Financial.

Shares of Under Armour rose 3.2% after hours, while Navient was up 0.4%. The shares of companies joining the S&P 500 often rise because many portfolio managers try to track the index and thus move to buy shares of companies that become part of it.